Ken, I agree with you on 95% of things that you said! Honda?? Well, their engines are still dead in mid revs after more then 20 years of development; IMO! M3(e46) is having decent "amount of meat" in mid range, at least.
I tried Cayman S and IMO it is very close to my Boxster S. Cayman's engine has more torque in mid revs and is little more eager to rev. On the road(steering feel, brakes etc.) they are IMO more or less-same... And I agree with you that Cayman S(and Boxster S, I will add) is more fun to drive then M3! Personally, I hate metallic sound that M3 is making when you rev it hard(around 7800-8000rpm)! Cayman S engine is powerfull, with nice Porsche boxer sound but, smooth! Top combo, IMO.